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Developing Novel Algorithms to Simultaneous Power Regulation and Load Mitigation of Modern Variable Speed Wind Turbines

Golnary, Farshad | 2022

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  1. Type of Document: Ph.D. Dissertation
  2. Language: English
  3. Document No: 55714 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Moradi, Hamed
  7. Abstract:
  8. The power control of horizontal axis wind turbines can affect significantly the vibration loads and fatigue life of the tower and the blades. In this thesis, we are going to consider both the power control and vibration load mitigation of the tower fore-aft vibration. For this purpose, at first, we developed a fully coupled model of the NREL 5MW turbine. This model considers the full aeroelastic behavior of the blades and tower and is validated by experiment results, comparing the time history data with the FAST (Fatigue, Aerodynamics, Structures, and Turbulence ) code which is developed by NREL (National Renewable Energy Lab in the United States). In the next, to estimate EWV, a novel hybrid approach was developed by combining a sliding mode observer and an adaptive neural fuzzy inference system (ANFIS). Novel sensorless control algorithms are developed based on the super twisting sliding mode control theory and sliding mode observer for disturbance rejection (by using EWV as an input). In region 2 (the wind speed is between the cut-in and rated wind velocity), the novel sensorless control algorithm increased the power coefficient in comparison to the indirect speed control (ISC) approach which is the conventional method in the industry. In region 3 (the wind speed is between the rated and cut-out speed), at first, pitch sensitivity is estimated by using a proper ANFIS system. The simulation results demonstrated that our novel approach improves the power coefficient efficiency by nearly 2% in region 3 in comparison to the ISC approach. In region 3, the developed approach reduces the standard deviation of the flapwise vibration of the blade by nearly 20%. We also consider the problem of lateral active vibration control of the tower and power control in region 3. We demonstrated a way how to solve the trade-off problem of active lateral vibration control by using the generator torque and power control in region 3
  9. Keywords:
  10. Nonlinear Modeling ; Blade Element Momentum Theory ; Onshore Wind Turbine Control ; Load Mitigation ; Renewable Energy Resources ; Power Control

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